AU593581B2

AU593581B2 - Surgical clip, applier, and method

Info

Publication number: AU593581B2
Application number: AU63250/86A
Authority: AU
Inventors: Robert B. Cushman; Zhu Yuong Hua; Wolff Mayer Kirsch
Original assignee: University of New Mexico UNM
Current assignee: University of New Mexico UNM
Priority date: 1985-10-15
Filing date: 1986-09-30
Publication date: 1990-02-15
Anticipated expiration: 2006-09-30
Also published as: SE9000183L; GB2181356A; SE9000183D0; IT1218121B; GB8623961D0; DE3633124C2; FR2588467B1; JP2599577B2; GB2181356B; IT8684144A0; SE467723B; DE3633124A1; FR2588467A1; AU6325086A; SE8604346D0; IN165360B; JPS63260545A; SE467722B; JP2642098B2; US4733664A

Description

593581 This doculjcnlt cntains the amendments mnace u' Section 49 and is con-ect lu1 COMMONWEALTH OF AUSTRALIA 9 t Patents Act 1952 t e Name of Applicants: THE UNIVERSITY OF NEW MEXICO and ROBERT B. CUSHMAN Address of Applicants: Albuquerque, New Mexico 87131, (i ~United States of America.

Box 435, Cedar Crest, New Mexico 87008, United States of America Actual Inventors: Wolff Mayer Kirsch, Yuong Hua Zhu, Robert B. Cushman COMPLETE SPECIFICATION FOR THE INVENTION ENT.TLED:- "SURGICAL CLIP, APPLIER, AND METHOD" The following statement is a full description of the invention including the best method of performing it known to us:- -1- 1 111\ 11- 414£ tt 4r C itt it it t C t CC tr BACKGROUND OF THE INVENTION THIS INVENTION relates generally to the field of surgery, and more particularly to the field of vascular micro-surgery.

In various surgical procedures, it is necessary to unite or reunite very small blood vessels, nerves and the like. The procedure of joining blood vessels is known as vascular anastomosis. Particularly in neurosurgical procedures and in the reattachment of severed body members, the number of anastomoses required can be very numerous, and accordingly, it is advantageous and frequently necessary to perform each such connection quickly yet properly.

A conventional end-to-end anastomosis is 15 illustrated in Fig. 1, which shows a pair of vessels 1 and 2, each held by a respective clamp 3 or 4 while it is sutured around its circumference. The vessel ends are first approximated by inward traction on the two vascular clamps. The vessels may then be preliminarily interconnected by placing sutures at two, three or four spaced locations around the circumference of the vessel note the threads 5 and 6 in tension whereafter the suturing 7 is completed with a needle 8. Various suturing techniques are known, all of which are designed 25 to: provide a leak-proof connection; provide adequate tensile strength; avoid unnecessary restriction of the vessel; avoid unnecessary tearing and other trauma to the vessel; and promote -2tc 4 a r 5 1

I

4 t 44 1 Sel

C

4 S *r 4 S S

I

rapid and thorough healing. Some of these objectives become increasingly difficult to satisfy as smaller and smaller anastomoses are carried out; furthermore, the danger of accidentally catching the rear oR distal wall of a vessel with the needle as the proximal wall is being sutured increases with diminishing vessel size.

With all vascular suturing techniques, thrombosis or clotting tends to occur at the points of needle penetration. While this clotting would not usually be sufficient to occlude larger vessels, in smaller veins and arteries a significant constriction or complete occlusion of the vessel can result from clotting. The problem has been summarized thus: "It is apparent to us that the damage to vascular endothelium 15 caused by the microvascular needle perforation is considerable. The amount of subsequent platelet aggregation and clot formation can be extensive, and these platelets are known to release vasoactive substances that can alter. vessel diameter. This could diminish blood flow through a 1- to 2-mm vascular anastomosis expected to give immediate increased flow to an underperfused region of the brain." D. Pagnanelli et al, The Cutting Edge Microsurgical Needle, Journal of Nerurosurgery, volume 59, ni. 3, pages 510-512 (Sept.

25 1983).

In addition to the physiological damage done by suturing, it is also significant that suturing, particularly of small vessels, is a very tedious time- -3-

C

consuming procedure which can preoccupy and fatigue a surgeon over the course of a long procedure. A more rapid way of performing micro-vascular anastomoses could free the surgeon for other tasks, and could shorten surgical procedures as well. The need for a workable, rapid, non-suturing technique for microsurgery is obvious.

Various non-suture devices and techniques for performing anastomoses are known, particularly for intestinal and colorectal anastomeses, for which various stapling apparatus and methods have been known for some years. Known stapling techniques, however, require penetration of the organ wall, and if applied to vascular anastomoses, the problems of clotting and the r** like, as described above, could be expected to arise.

4 t I For vascular anastomosis, various other non-suture Smechanical clamps have been suggested. Such clamps t frequently include a permanent or sacrificial ferrule or the like and means for clamping the vessel against the 20 ferrule so that penetration of the vessel wall is avoided. However, clamps of this type have not gained 4 ;widespread acceptance.

In view of the foregoing, this invention has c r C been made with a view to substantially increasing the CC C 25 speed of microvascular anastomoses and other procedures while avoiding the clotting problems caused by conventional suturing procedures. Another object is to reduce the material costs and duration of ia 4 a r *4 r *r microsurgical procedures.

A further object of the invention is to provide a permanently implantable surgical clip for use in place of microvascular suturing. Yet another object is to provide the surgeon with a clip that can be easily held and applied during vascular anastomoses.

This invention relates generally to a surgical procedure such as an anastomosis wherein a pair of tissues is approximated, then partially everted, and then joined by placing the arms of a surgical clip over the adjoined tissues and crimping the arms about the tissues in such a way as to hold the tissues together without penetrating them.

The invention is also directed to a vascular 15 surgical clip comprising a plastically deformable4 bedy portion, a tang for deforming the4 bedy, and a neck connecting the tang to theheby, wherein the neck is designed to break upon application of a predetermined tensile force to the tan, and the4bed being designed to deform upon application to the tang of less than said predetermined tensile force.

In a further aspect, the invention is directed to a tool for applying the subject clip. In its broadest sense, the tool includes means for gripping and 24 applying tension to the tang, and means for simultaneously pushing against shoulders on the clip body. The tool enables the surgeon to perform the subject method by using the tool first to manipulate 9 t (r

I!:

trl i 5 S. i- se r" ~gCLL:r~~~ :i -i C C t r V Ct C 4£ the clip into position over opposed tissues. Then by squeezing or otherwise manipulating the tool, he deforms the clip so as to capture the tissues between the clip's arms and thereby hold the tissues permanently together.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated by the following description of a preferred embodiment and by the drawings, wherein: Fig. 1 illustrates a prior art suturing method described above; Fig. 2 is an oblique view of the inventive clip in its original, undeformed condition; Fig. 3 is a view similar to Fig. 2 showing the clip in a partially deformed condition; Fig. 4 shows the clip in its fully deformed condition; Fig. 5 is an elevational view of the inventive clip applier; Fig. 6 is an enlarged view of a portion of Fig 5. and Fig. 7 is a view similar to Fig. 1, illustrating the inventive procedure.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in Fig. 2, a surgical clip embodying the invention is formed of a unitary piece of biologically acceptable, plastically deformable material such as a noble metal gold, silver, platinum, etc.). While metal clips are presently 44 C I 4 rrr 25 c i ~dl ii? 1 r preferred, it is contemplated that other materials such as suitable polymer plastics may be used. Whatever the material, it must be sufficiently ductile or plastically deformable so that when the clip is crimped there is minimal spring-back. Otherwise, possibly injurious overcrimping, to compensate for the spring-back, would be required.

Structurally, the clip includes a pair of inwardly curved arms 10 and 11 interconnected by a parallel in one direction from the- iging3eci.

The arms terminate at tips 15 and 16 which are rounded to prevent injury to the subject tissue in accordance *'er «with an object of this invention. The bridge portion 12 S; 15 includes a pair of shoulders 17, 18 for engaging the o |applier tool described below. The centre of the bridge c C is integrally connected to a tang 19 preferably having l t e an enlarged head 20. The connection point is a neck 21 of reduced cross-section designed to break when a Vt t 9, 20 predetermined tension is applied to the tang by the tool. The size of the neck is such that its breaking ,.t 1 r strength ("predetermined tensile force" in the claims below) is greater than the tension required to deform, e' r 25 by bending, the bridge portion of the clip.

The size of the clip will naturally vary F .according to the application, and we do not intend to limit the scope of this invention to any particular size clip. However, merely as an example, for the S-7- L anastomosis of a l-mm vessel, an appropriate size clip has an overall height on the order of .030 inches and an overall thickness on the order of .006 inches. For this size clip, the radius of curvature of the tip of each arm is approximately .0005 iLiches.

To deform the clip, tension is applied to the tang 19 by a tool such as that described below, while the shoulders are supported by stationary jaw faces on the tool (Fig. The relationship of the jaw faces and the clip shoulders is preferably such that the points of engagement are substantially spaced; i.e., such points are initially remote from the neck. Because of this geometry, application of a tension T to the tang 1 produces a bending moment M TX/2 at the centre of the 15 bridge, where X equals the distance from the tang axis C, to either contact point, as shown in Fig. 3. The neck is sufficiently strong that a bending moment large enough to deform the bridge portion can be produced (Fig. In designing the applier and the clip, the v 20 abutting surfaces of the clip shoulders and the jaw faces are so designed that once a desired degree of C« r bending deformation has occurred, the contact points move much closer to the neck, whereafter even substantially increased tang tension does not generate a bending moment sufficient to cause bridge deformation, but rather ultimately fractures the neck 21 (Fig. A particular advantage of this feature is that the amount of bridge deformation is accurately determined by the -8- 0 1

V"

4f *c I 'I (CS I (C t I *I Ii .4 (4 11( clip/tool geometry, and is thus independent of the surgeon's manipulating force. As a result, the deformation from clip to clip and from surgeon to surgeon is highly reproducible for a given clip/tool combination. Furthermore, one of skill in the art will appreciate how simple changes in jaw face geometry or clip shoulder shape could be made to produce desired changes in the degree of clip deformation.

Figs. 5 and 6 show a clip applier constructed in accordance with this invention. The applier includes means for gripping a clip tang, preferably in the form of a single movable jaw 50 having a slot 52 sized to receive the tang, which slot has an enlarged pocket or recess 54 sized to receive the tang's head. The jaw is 15 supported in a body 56 that terminates at a forward end defined by stationary jaw faces 58, 60 astride the slot and designed to engage the shoulders 17, 18 on the clip. In the embodiment shown, the jaw faces 58, 60 are

A

planar and have between them an obtuse angleA of approximately 120 degrees, which is less than the angle B of approximately 150 degrees between the clip shoulders. Comparing Figs. 3 and 4, one will note the inward shift in contact point location which results from this geometry as the clip deforms.

The jaw is retracted away from the abutment faces by any of several mechanisms, most preferably a cam-actuated device responsive to squeezing pressure from the surgeon's hand. In this embodiment, shown in ;i i i:' -9 i: (i 7 "i r r 4g 4 t 41 1 S.

4 $S

I

4 4, I tA C .!4 4 4 C 4' 4 Fig 5, the applier body 56 includes a pair of flexible leaves 62,64 interconnected at both ends and movable toward each other when the tool is squeezed by the surgeon. Each leaf has an inner surface from which a cam 66 protrudes, the cam having an actuating surface 68 oblique to its direction of movement. As viewed in Fig. 5, the cams are symmetrical in profile, and overlap so as jointly to engage a common cam follower 70. This follower is connected to the jaw 50 as shown. When the leaves are squeezed together, the cam surfaces approach one another, causing the movable jaw 50 to retreat with respect to the stationary jaw faces 58,60. When a clip is in place within the tool, this action causes deformation as previously described. In Fig. 5 the arcuate shape of the cam faces 68 is noteworthy. This shape makes the ratio of squeezing force to retracting force an increasing function, giving better feel in situations where it is desired intentionally to limit clip deformation to less than that .dictated by the 20 shapes of the abutting surfaces.

While the retracting mechanism is preferably purely mechanical for reasons of simplicity, other mechanisms, such as a fluid-driven piston, or an electrically actuated solenoid, are also contemplated.

25 In any event, what is required is a safe, reliable mechanism for retracting the jaw with respect to the body, responsive to a simple manipulation by the surgeon.

I

4: 10 8! i

I

r

I

i T a It will be appreciated that the proper geometry for the clip depends on the shape of the applier's jaw and abutment surfaces, and vice-versa.

Therefore, these two items must be co-operatively designed.

Fig.7 illustrates an end-to-end microvascular anastomosis employing the clip and applier described above. In this procedure, a pair of tissues to be joined are first drawn together in apposition (approximated) by suitable means. The edges of the tissues should be partially everted, that is, pursed or flanged outwardly approximately 90 degrees from the axial direction, so that a clip can be placed over the i tissue edges, with the arms of the clip astride the i 15 point of apposition. Care must be taken not to allow the vessel to cuff back over on itself, since the joint ultimately produced would be weaker than the flanged I f configuration. Once the clip has been positioned properly with respect to the subject tissues,, crimping Ia, 20 is effected simply by squeezing together the leaves of S the tool. This causes permanent deformation of the microclip bridge section 12, whereafter the clip arms 10,11 retain the tissues in apposition without 'puncturing them. This procedure is repeated at as many 25 points as are needed to join the subject tissues securely. The clips, being biologically inert, ordinarily may be left in place permanently. However, in the event that the clip must be removed, a suitable -11g4~

QI.

.4 C

~C

r~ I t *gaI.

9* 99~9 9 9 I I

CIII

II IC e c C tool may be used to spread the arms 10 and 11.

The clip and applier tool described above provide a sutureless means for the apposition of tissue which is substantially faster than conventional suturing methods, particularly in microvascular anastomosis and which avoids the clotting problem caused by needle perforations. In testing on femoral arteries in rats, short and long term patency and remarkably little damage to'the vascular endothelium have been observed.

An advantage of 'the inventive clips over sutures is the predictability of results. In contrast to hand-made micro-suturing needles, the masproduced microclips are uniform, producing more uniform results.

15 An additional advantage is that the speed of application reduces the time blood supply is interrupted, enhancing prospects for vessel patency.

Another advantage is that on any tissues joined in accordance with this invention, the clips are 20 physically independent of one another. Thus, although they securely hold the tissues together at individual points, the clips can move with respect to one another.

As a result, their spacing can increase as tissues grow.

This makes the present invention particularly attractive for performing anastomoses in children, whose vessels must later expand. Permanent sutures (Fig. 1) must of course be removed if they are not to interfere with vessel growth.

-12-

A

It should be understood that the foregoing description and drawings describe and illustrate but one embodiment of the invention, whose scope should be measured by the following claims.

a.

4* a a9* a 9* 1 a.: It a. a: a a a a.

a ja. a 9a 0 9 .0 0 0 0* *0*4 4* 0 at.: a t a t a at a I 13

I

Claims

1. A surgical clip, comprising a plastically deformable bridge portion, a tang for deforming said bridge portion, and a neck connecting said tang to said bridge portion, said neck being designed to break upon application of a predetermined tensile force to said tang, said bridge portion being deformable by application to the tang of less than said predetermined tensile force.

2. A surgical clip comprising a plastically deformable bridge portion, a pair of spaced arms extending generally parallel in one direction from opposite ends of said bridge portion, $of, a tang extending from said bridge portion in a direction opposite that of said arms, for deforming said t bridge portion so as to bring said arms together around opposed tissues, Sa neck connecting said tang to said bridge portion, I t said neck being breakable upon application of a predetermined tensile force to said tang, said bridge portion being deformable by application to the tang of less than said predetermined tensile force.

3. The invention of claim 2, further comprising an enlarged head on said tang to facilitate gripping thereof by an applier tool.

4. The invention of claim 2, wherein each of said arms is arcuate and has a concave surface facing the other arm SA X l whereby tissue may be retained between the arms when the bridge is deformed.

The invention of claim 4 where said arms terminate at distal tips which are sufficiently rounded to avoid puncturing tissue captured between said arms when said bridge is deformed.

6. The invention of claim 2, further comprising a pair of spaced shoulders on said bridge portion, one on either side of said neck, for supporting said clip as tension is applied to said tang, to create a bending moment in said bridge for deforming the same.

7. The invention of claim 6, wherein said shoulders are generally flat so as to limit deformation of said when tension is applied to said tang.

8. The invention of claim 7, wherein said shoulders lie .It. t at an obtuse angle in the range of 120 degrees with respect to one another. S.

9. The invention of claim 7, wherein said shoulders lie S' t at an obtuse angle of about 120 degrees with respect to one another.

A tool for deforming a surgical clip as claimed in any one of the preceding claims comprising I* means for gripping and applying tension to said t iI S'1 tang, and means for simultaneously engaging said surgical clip at said bridge portion.

11. The invention of claim 10, wherein said engaging Al I means comprises a pair of spaced stationary jaw faces adapted to engage shoulder portion on said bridge portion.

12. The invention of claim 11 wherein said jaw faces are generally flat, and lie at an obtuse angle in the range of 120 degrees to 180 degrees with respect to one another.

13. The invention of claim 12, wherein said obtuse angle is about 150 degrees. r 11 41 I Ic I cc t Ct C C Cl

14. The invention of claim 11, wherein said gripping and tensioning means comprises a jaw moveable with respect to said stationary ja. faces, and means for retracting said movable jaw.

The invention of claim 14, wherein said retracting means comprises a cam and a cam follower, said cam being connected to manipulable means on the applier, and said follower being connected to said movable jaw.

16. The invention of claim 15, wherein said manipulable means comprises at least one flexible leaf affixed to said body, a portion of said leaf being deflectable by finger pressure with respect to said body, said cam being mounted on said movable portion.

17. The invention of claim 16, comprising two of said leaves, each being integrally connected, at both its ends, to said body whereby the central portions of the leaves can be moved toward one another by squeezing the applier.

18. The invention of claim 15, wherein said cam includes an actuating surface lying oblique to the axis of movement of said movable jaw, and said follower is engaged by said -T RAZ/ 1Lcrr II~ 4I *s 4 I I 4r r- 4 i 1 *r 4 61 1 actuating surface.

19. The invention of claim 18, wherein sa.'d actuating surface is arcuate.

The invention of claim 18, wherein said follower is a roller.

21. The combination of: a surgical clip comprising a plastically deformable bridge portion, a pair of spaced arms extending generally parallel in one direction from opposite ends of said bridge portion, a tang extending from said bridge portion in a direction opposite that of said arms, for deforming said bridge portion so as to bring said arms together around opposed tissues, a neck connecting said tang to said bridge portion, said neck being breakable upon application of a predetermined tensile force to said tang, said bridge portion being deformable by application to the tang of less than said predetermined tensile force, a pair of shoulders on said bridge portion, one on either side of said neck, said shoulders being defined by bearing surfaces having an obtuse angle B between them, and a tool for deforming said clip, comprising means for gripping and applying tension to said tang, and including a pair of spaced stationary jaw faces adapted to engage said clip shoulders respectively, wherein said jaw faces are generally flat, and lie at an obtuse angle A with 17 64*$ 6 I Ic I iI I' I 1 i r- ~aaj 1'' r respect to one another, wherein said angles are defined by the relationships 120 degrees <A <180 degrees, B <180 degrees, and A<B.

22. The invention of claim 21, wherein angle B is about degrees greater than angle A.

23. A method of performing a surgical anastomosis comprising steps of aligning a pair of blood vessels, everting the tissue edges by about 90 degrees so that the vessel intimal surfaces face one another, opposing said surfaces, and closing a plurality of clips as claimed in any one of claims I to 9 around said edges at spaced locations so as permanently to hold said vessels together, while allowing for circumferential expansion thereof.

24. A method of joining biological tissues comprising steps of aligning edges of said tissues, everting said edges by about 90 degrees so that the tissue surface face one another, and Sclosing a plurality of clips as claimed in any one of claims 1 to 9 around said edges at spaced locations so as Sto permanently to hold said tissues together, while allowing for growth thereof. DATED this day of 3 S C. 1989. THE UNIVERSITY OF NEW MEXICO and ROBERT B. CUSHMAN By Their Patent Attorneys G R CULLEN CO 1 T O i 0,